Colin Kaepernick, Harbaugh's most important project, started and played poorly in both games.

There's a perception that the biggest reason for Kaepernick's struggles in those games was the CenturyLink Field crowd noise.

Pete Carroll and Russell Wilson have been all smiles in 2013.Streeter Lecka/Getty Images

To be sure, the Pacific Northwest fans played a part. But it's possible that the bigger problem is the Russell Wilson-Carroll tandem is simply better than the Kaepernick-Harbaugh duo.

Okay, okay. That's a strong assertion. And let's not forget the circumstances heading into each game.

Last year, the 49ers had already clinched a playoff spot and held a 1.5-game division lead when they took the field against the Seahawks in Week 16 on Sunday Night Football. Essentially, the Red and Gold had nothing to play for. On top of that, defensive tackle Justin Smith missed his first game of the season with a biceps injury.

Meanwhile, the Seahawks were a win away from clinching a playoff spot. They had lost three times in a row to the Harbaugh-led 49ers, including a 13-6 setback in Week 7 at Candlestick Park. The Seahawks desperately wanted revenge, and they played like it.

You all know what happened after that. The 49ers clinched the division the next week. In the playoffs, the Seahawks lost to the Atlanta Falcons in the divisional round. San Francisco beat Atlanta in the NFC Championship Game before losing to the Baltimore Ravens in the Super Bowl.

Both the Seahawks and 49ers entered their Week 2 Sunday Night Football matchup this season coming off Week 1 wins. All the talk was about Wilson and Kaepernick, two of the best young quarterbacks in the NFL. After Kaepernick threw for 412 yards and three touchdowns against the Green Bay Packers, many believed he was ready to take down the Seahawks in Seattle.

Colin Kaepernick's 20.1 passer rating against Seattle in Week 2 was the worst mark of his career.Steven Bisig-USA TODAY Sports

Instead, it would mark the beginning of a Kaepernick slump.

The third-year signal-caller had just 127 passing yards and three interceptions in the 29-3 loss. It was the worst performance of his NFL career.

San Francisco might be without starting offensive linemen Joe Staley and Mike Iupati, but enough with the excuses. This game is in San Francisco, and Crabtree is playing. The 49ers are fighting to even make the playoffs, whereas the Seahawks can afford two more losses and still clinch the No. 1 seed in the NFC playoffs.

To put it simply, the 49ers need this game more. And this time, they're the team desperately wanting to make a statement.

"Any time you play a team and you lose, the next opportunity you get to play them again, it's definitely a statement game," Vernon Davis was quoted as saying to Jimmy Durkin of the San Jose Mercury News.

Harbaugh stated it a bit differently than Davis. The head coach said he's looking for "validation," per Andrew Pentis of 49ers.com.

It's an interesting word choice from Harbaugh. He wants to find out the truth about his team.

Jim Harbaugh has a 3-2 record against Pete Carroll in the NFL.Kirby Lee-USA TODAY Sports

A win over the Seahawks would put the 49ers right back in the Super Bowl conversation. It would even the head-to-head score between Harbaugh and Carroll over the last two seasons.

But what would a loss mean?

Of course the Niners would be one step closer to missing the playoffs entirely. But it would also be Carroll's third consecutive win against Harbaugh, and his first ever in San Francisco.

The narrative on Harbaugh would shift from NFC's best coach to second fiddle in his division.

At this point, many of you might be thinking that I'm overhyping this game. After all, the 49ers could lose and still roll through the NFC playoff bracket to the Super Bowl. Anything is possible when a team gets hot right before the playoffs start, as Tim Kawakami of the San Jose Mercury News noted:

However, keep in mind that the core 49ers players—Kaepernick, Davis, Patrick Willis, NaVorro Bowman and Aldon Smith—participated in the last two losses to the Seahawks as well. These are the players that are supposed to lead the team over the next few years. As I alluded to earlier, maybe the Seattle core of Wilson, Marshawn Lynch, Earl Thomas, Richard Sherman and Bobby Wagner is simply better than San Francisco's core.

And if you disagree with the idea that the Seahawks have more talent, then the logical finger-pointing goes to San Francisco's coaching staff if the Niners lose to their division rivals again.

On Sunday, the Seahawks have an opportunity to not only clinch the division title, but to also leave no doubt that they're the team to beat in the NFC West in 2014 and beyond.

That scenario would eat away at Harbaugh. The 49ers, already 1-4 against teams with winning records in 2013, can't afford another confidence-deflating loss.

Harbaugh knows it. One way or the other, he'll find out the truth about his team on Sunday.